DIRECTION must be entered in degrees, increasing 'counterclockwise'. In rather unscientific terminology, a vector pointing directly to the 'right' has a direction of zero degrees. A vector pointing straight 'up' has an angle of 90 degrees. A vector pointing to the 'upper left' is at a 135 degree angle and so on. (see diagram below)

MAGNITUDES can be in any units but you must BE CONSISTENT. For example, if you are inputting pounds then ALL magnitudes have to be in pounds. The same would apply to newtons, dynes, etc. So you may use any magnitude units you like but DO NOT MIX UNITS.

As a practice example try entering these 4 vectors:

Scroll down to the bottom and click CALCULATE. Your answers should be:

5.6337 newtons and 158.35 degrees.

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Here's hoping this calculator either meets or exceeds ALL your vector addition requirements.
Good luck with those physics problems !!!